1. Field of the Invention
The present invention relates to a cerebrovascular analysis system for analyzing the cerebrovascular diseases by measuring a biodynamic property and a blood flow property in a cerebral blood vessel, more specifically to a cerebrovascular analyzer for an early diagnosis of a cerebral thrombosis and other cerebrovascular refractory diseases by defining a cerebrovascular system as the blood vessel system organized with an internal carotid artery branch, an anterior cerebral blood vessel branch, a middle cerebral blood vessel branch, a posterior cerebral blood vessel branch, a vertebral artery branch and a basilar artery branch and then by analyzing each cerebrovascular branch of the cerebrovascular system to show a organic change of blood vessel by calculating a elastic coefficient of blood vessel and to show a blood flow property and organic and functional changes of the cerebrovascular system simultaneously by measuring a compliance of blood vessel, a resistance of blood flow and a volume of blood flow.
2. Description of the Related Art
In the today's clinics, an ultrasonic Doppler system is used to early diagnose the cerebrovascular diseases. However, the ultrasonic Doppler system has a limit to apply in clinics due to the incapability to measure the property of blood vessel.
Several cerebrovascular disease analyzers are developed until now such as angiography, MRA, FMRI, SPET, TCD, TEE, TTE, QFM and CVD.
The advantage of the angiography among them is that it is able to directly observe the progress of the diseases of blood vessel itself, but a blood vessel invasive operation is basically needed to inject a contrast medium and the operation is complex.
MRA and FMRI are the analyzing system to overcome the defects of the angiography, but they are only used in a certain ward due to the high cost of manufacture and diagnosis.
Especially, MRA, FMRI and SPET are used to identify a distribution of blood vessel, a blood flow property, a region of low blood flow, etc., although some differences are existed each other, but the property of blood vessel is not identified by them.
The ultrasonic quantitative flow measurement system (QFM) and the cerebrovascular property measurement system (CVD) enable to calculate the volume of blood flow of the carotid artery and the compliances of the middle cerebral artery and the anterior cerebral artery with low cost.
However, in order to assess the organic and functional states of blood vessel characterizing the blood vessel property, it is needed to know information of the elastic coefficient of blood vessel, the compliance of blood vessel and the resistance of blood flow, etc., for reflecting the organic and functional states of blood vessel itself rather than information related to the blood flow state such as a volume of blood flow in blood vessel and a blood pressure acted on the blood vessel wall.
However, it is a very difficult problem to measure the elastic coefficient of blood vessel, the compliance of blood vessel, a diameter of blood vessel, the resistance of blood flow and the volume of blood flow in each blood vessel branch of the cerebrovascular system for reflecting the organic state of blood vessel.
It is caused by the facts that the cerebovascular system has a complex structure and the biodynamic actions of blood vessel branches are different each other in the cerebrovascular system. It is also caused by a practical impossibility of the most accurate method that measures the elastic coefficient as an indicator of the organic change of blood vessel in human body by pulling a blood vessel sampled from living body with a tension apparatus.
In 2002, Werner G, Marifan C, Tonny M, Jeffrey C, etc., professors of California University in U.S.A, studied on biodynamic property of cerebral blood vessel of human and published a paper as Mechanical and Failure Properties of Human Cerebral Blood Vessels which is related to the property of the cerebral blood vessel.
However, because the blood vessels of human were sampled and tested, the results of the experiment can't be used as the indicators to diagnose.
Various researches on the indirect measurements of the volume of blood flow, the compliance, the elastic coefficient, the resistance of blood flow, etc. in the cerebrovascular system have been going on.
From 1997 to 2004, the measurements of the compliance and the resistance of cerebrovascular system had been suggested by many researchers such as Biedma, Haoliu, Cwako shin, etc. in U.S.A.
However, the above research results only contained the general facts on the blood pressure, the compliance, the elastic coefficient, the resistance and the distribution of blood flow in the cerebrovascular system, but did not obtain contents to apply the clinics directly.
In 2006, KF-3000 apparatus to apply to the clinics was developed by Ding Guanghong, a professor of Fudan University in Shanghai, China, to calculate the blood flow volume of each blood vessel branch in the cerebrovascular system.
KF-3000 brought to the innovative results to obtain the property of blood flow in the cerebrovascular system, but KF-3000 did not develop TCD to early diagnose the cerebrovascular diseases due to the intangibleness of the property of blood vessel.
Unlike the study of Dr. Ding Guanghong, COLLIN in Japan suggested a ultrasonic quantitative flow measurement system, QFM-2000X, to assess the property of blood flow and the property of blood vessel in cerebrovascular system for early diagnosing the cerebrovascular diseases and also CVD-1000, as a similar apparatus to QFM-2000X, based on a pending patent, an apparatus measuring parameter of cerebrovascular and method thereof.
The features of the ultrasonic quantitative flow measurement system (QFM) and the pending patent, an apparatus measuring parameter of cerebrovascular and method thereof, are organized to show a possibility to early diagnose the cerebrovascular diseases by calculating the volume of blood flow of the internal carotid artery, the compliances of the middle cerebral blood vessel and the anterior cerebral blood vessel with low cost.
However, the features of the ultrasonic quantitative flow measuring instrument (QFM) and the above pending patent could not identify separately the organic change and the functional change as two basic properties of blood vessel by selecting the compliance of blood vessel and the blood flow indicator as basic measurement indicators.
Especially, the ultrasonic quantitative flow measurement system (QFM-2000X) and the cerebrovascular property measurement system (CVD-1000) showed several defects to calculate the compliance and the resistance of the cerebrovascular system.
QFM-2000X calculated the compliance C and the resistance R to assess a left cerebrovascular system and a right cerebrovascular system under the assumption that the cerebrovascular system is divided to left and right and the blood flow volume of the cerebrovascular system is the volume of blood flow which flows into the internal carotid artery.
Therefore, it was not able to assess each blood vessel branch of brain.
Also, to obtain the compliance and the resistance of the cerebrovascular system, the features of them considered a blood pressure waveform as a pressure pulse waveform and a blood flow waveform as an ultrasonic waveform and calculated C and R by adjusting the waveforms to coincide with each other, but the results of C and R had defects that the amplitude of vibration was large and the approximation of curve was largely different from real phenomenon.
In fact, when the blood flow waveform is measured by the ultrasonic Doppler, the measurement error is very large due to the error of horizontal level. Therefore, the coincidence of two waveforms with the errors is not real and has very low reproducibility. Additionally, the approximation of curve vs. curve creates a big error by very little waveform change.
Therefore, the compliance C and the resistance R measured by QFM-2000X does not an enough mortgage to use as the clinical indicators because the values of C and R are differed 10-100 times from each examiner due to the irreproducibility.
The configuration of the pending patent, an apparatus measuring parameter of cerebrovascular and method thereof, could not find an accurate clinic indicator by assuming that when the cerebrovascular system is modeled and analyzed, the volume of blood flow which flows into the brain is equal to k times of the volume of cardiac output instead of calculating the volume of blood flow which flows into the brain.
The configuration of the pending patent, an apparatus measuring parameter of cerebrovascular and method thereof, is suggested as followings.
Although the cross-unital area of the internal carotid artery is reduced to 80-90%, the blood flow volume which flows into the internal carotid artery does not changed. Accordingly, the blood flow volume of the internal carotid artery can be calculated by an equation Qc=KcSv, where, Sv is a cardiac output and Kc is a ratio coefficient.
However, the above assumption did not an enough mortgage as a medical diagnosis apparatus.
Also, the configuration of the pending patent, an apparatus measuring parameter of cerebrovascular and method thereof, reduced the correctness of disease diagnosis by assuming that the compliances and resistances of the anterior and posterior cerebral arteries were divided by a predetermined rate.
Specifically, QFM-2000X and the pending patent, an apparatus measuring parameter of cerebrovascular and method thereof, did not suggested a method to obtain the compliance and resistance of the posterior cerebral artery.
Accordingly, QFM-2000X and the pending patent, an apparatus measuring parameter of cerebrovascular and method thereof, did not obtained the elastic coefficient, but obtained the compliance and the resistance for assessing the property of the cerebrovascular system. However, the obtained compliance and resistance showed many defects.
Therefore, it is needed new solution to accurately calculate the elastic coefficient, the compliance, the resistance, and the volume of blood flow of each blood vessel branch in the cerebrovascular system.